Switch edition

Is Britain’s nuclear arsenal fit for purpose?

This week’s revelation that a missile from a British submarine malfunctioned last year during a test flight off the coast of Florida has raised concerns about our ageing Trident missile system. Is it safe?

Alarm concerning the safety of the UK nuclear submarine fleet is understandable. The Sunday Times revealed on last week that there had been a malfunction during a missile test off the coast of Florida in June last year. The £17m missile, fired from the nuclear submarine HMS Vengeance, had been supposed to fly across the Atlantic towards Ascension Island, off the coast of Africa. The Royal Navy boasts that such missiles have an accuracy to within a few feet, even after a flight of thousands of miles. But in this case, it was out by considerably more than a few feet – the flight had to be aborted as the missile headed in the opposite direction, towards Florida. In the middle of the week, there was another revelation, this time from declassified CIA material: in 1974 a US submarine, carrying 16 Poseidon nuclear missiles, was leaving the Holy Loch on the Clyde when it collided with a Russian submarine that had been tailing it.

So lots of reasons to be worried?

One of the most troubling aspects is not just that the missile went astray, or that the public was never informed about the 1974 collision, but the secrecy of the British government. Even now, neither Downing Street nor the Ministry of Defence will officially admit that the test-firing went wrong. We still do not know for sure if the government deliberately concealed this because it did not want the news to undermine a Commons vote to sanction spending on a new generation of nuclear submarines. And we still do not know what caused the missile to go astray. Defence sources, speaking informally, have said that the submarine performed as it should. The problem was the missile, which was not a UK problem – the UK just picked one at random from the US stockpile. It could just as easily have been a US submarine that fired it. Anyway, said these sources, it was a “minor” incident. When the malfunction was identified – a problem with “telemetry”, the navigational system – the missile was aborted. But that is not entirely comforting. It is one thing to abort a test missile – a small explosion is detonated – and another to abort a nuclear warhead.

What is the state of the nuclear fleet?

The UK’s nuclear fleet is ageing and there are regular reports that the four nuclear submarines that make up the fleet – HMS Vengeance, Vanguard, Victorious and Vigilant – are creaking. The date for replacements keeps slipping back and is now set for the early 2030s. Opponents of nuclear weapons counter that these stories are overplayed and that it is perfectly feasible to keep the submarines going beyond the 2030s; that such a delay would not only save money but allow an assessment of whether the case for nuclear weapons is still valid.

Does new technology threaten to make nuclear submarines redundant?

I visited a nuclear submarine last year, with the defence secretary Sir Michael Fallon. During a Q&A session I suggested that by the 2030s new technology such as underwater drones that can track submarines, or satellites that can detect large moving objects, would mean submarines were no longer hidden. And if they could not be hidden, they would lose their purpose. A deterrent only works if you are sure a submarine is not vulnerable to a preemptive strike. The bank of naval officers sitting behind Fallon shook their heads. The usual response is that whatever technology is developed to find subs, technology will also be found to help them stay hidden. But if it is possible to hack into the Pentagon, as happened five years ago, it is at least theoretically possible to hack into the communications system of a nuclear sub. Some of the speculation about the rogue missile last June is that it might have been hacked. It seems unlikely, but since the government declines to provide an explanation, it cannot be discounted.

There are lots of accidents. These are just the ones we know about. Just one example: in 2009, HMS Vanguard hit the French nuclear submarine Triomphant, in the Atlantic. The MoD said the vessels were moving at “very low speed”, as if that should somehow be comforting.

What are the chances of another error?

The standard of the crews aboard the nuclear subs is high. Elaborate procedures are in place and discipline is tight. But just getting out of a Scottish sea loch into open water, while at the same time escaping Russian detection, requires a lot of skill and risky manoeuvring. Sometimes they also turn off many of their sophisticated listening and navigational devices, in order to make themselves harder to find. But this also raises the risk of an accident. The military train all the time, often at the edge, and things often go wrong with planes, tanks, armoured cars or nuclear subs. But the number of casualties if a tank gun misfires is relatively small. What makes an accident involving a nuclear submarine so concerning is that each warhead is eight times more destructive than the bombs that hit Hiroshima.